The present invention relates to a needle-guide device, particularly for ultrasound probes, or the like, comprising a base body having means for connection to the probe and at least one elongated guide tube for an elongated, rodlike diagnostic or surgical tool, named needle.
Such devices are currently used to accurately guide diagnostic or therapeutic tools, such as needles for biopsy, thermoablation, alcoholization or localized injection of substances, especially of chemotherapeutic agents.
However, the word needle is used in the present description and in claims, to define any diagnostic or therapeutic tool for localized operation, which has a rodlike conformation, for at least a portion of its extension, for instance for a portion of a support stem of the tool.
Localized applications, such as biopsies, thermoablation or localized injection of therapeutic substances are currently performed in combination with imaging means, and particularly in combination with ultrasound probes. Ultrasonic imaging allows to see the needle, or at least one of the needles and the target region to safely orient and move the needle to the target point.
The needle/s are moved to their position by appropriately orienting the probe manually or mechanically and/or by sliding them inside a guide seat. Hence, the probe shall have a needle-guide for safely and stably accommodating the needle, thereby avoiding any mutual staggering and wrong positioning or insertion of the needle/s.
To this end, needle-guide devices such as the one described hereinbefore are known, which comprise an elongated cannula-shaped hole, or the like, wherein the needle is inserted.
These devices have the drawback of not allowing a sufficiently safe sterilization. In fact, hardly removable microbial residues may infiltrate in the elongated holes or cannulae. For this reason, single-use needle-guides of the above type are currently known, particularly made of plastic. However, this involves some drawbacks. Besides obvious cost drawbacks (considering that stable attachment of ultrasound probes often requires rather complex adaptations of the needle-guides, thereby involving rather high fabrication costs), material waste is caused, with a consequently higher environmental load and the materials in use do not often have a good stability, for instance to thermal action, which is a critical condition, in applications like thermoablation.
Therefore, the invention has the object of providing a needle-guide such as the one described hereinbefore which, by relatively inexpensive construction arrangements, allows to obviate the drawbacks of prior art needle-guides. Also, the invention has the object of improving needle-guides to achieve a better functionality with reference to the diagnostic and/or therapeutic techniques which use those tools.
The invention achieves the above purposes by providing a needle-guide as described hereinbefore, which is made of at least two removably connectable parts, which two parts are shaped in such a manner that each of them forms complementary parts of the peripheral delimiting wall of the elongated hole and/or cannula for the needle (3), which complete each other when said two parts of the needle-guide are connected, thereby forming an elongated hole for guiding the needle or a cannula with a 360° covering delimiting wall.
Particularly, the two needle-guide parts have mutual abutment surfaces which are tangent or secant to the elongated needle-guiding hole, whereas this hole is obtained by a combination of grooves which are formed either integrally on one of the mutual abutment surfaces of one of the two needle-guide parts or partly on one and partly on the other of the two abutment surfaces of both needle-guide parts.
The separation plane between the two needle-guide parts is parallel to the axis of the elongated hole and secant or substantially tangent to the hole.
The elongated needle-guiding hole may be provided with a section corresponding to the outer section of the needle, with the wall of the elongated hole adhering to the whole needle surface.
Possibly and advantageously, the elongated needle-guiding holes may also have polygonal, particularly square or rectangular sections, said square or rectangular sections having such a size as to be able to inscribe therein the cylindrical or elliptical or oval section of the needle. This provides the advantage of a wider range of position choices for the separation plane between the two needle-guide parts in the elongated hole area, there being no undercut situation if the separation plane intersects the hole with an orientation parallel to at least two sides thereof. Moreover, since the needle has to be held accurately as regards orientation but must be able to slide inside the hole in the direction of its axis, the use of rectangular or square holes limits the contact surfaces between the needle and the guide hole wall to individual tangent lines or bands, thereby obtaining a lower friction between the needle and the hole wall (friction force being also proportional to the contact surface) and an effective and safe hold of the needle in the oriented position.
According to an advantageous embodiment, the needle guide is composed of at least two removable parts, at least one base part and at least one second part, which two parts are separated from each other by a separation surface whose cross section is a broken rectangular curve, and forms a succession of alternate and parallel complementary engageable ribs, there being provided, in the opposite mutual abutment surfaces of the ribs of one or both of the two needle-guide parts, grooves having such a size and shape as to form together an elongated needle-guiding hole or cannula.
The broken rectangular line-shaped separation surface between said two needle-guide parts may have variable widths and generate guiding holes with different relative positions.
Obviously, the needle-guide may be divided in such a manner as to consist of more than two parts, for instance three parts, shaped in such a manner as to form complementary parts of the peripheral delimiting wall of the needle-guiding elongated hole or cannula.
Advantageously, in a preferred embodiment, the needle-guide is composed of a base for connection to the ultrasound probe, which has at least one longitudinal groove, for engaging longitudinally continuous or discontinuous extensions of the side walls of a longitudinal groove provided in the other needle-guide part. Here, the bottom of the longitudinal groove in the base forms the complementary part for completing the elongated hole or cannula, whose other peripheral walls consist of the bottom of the longitudinal groove of the other needle-guide part, of the side walls of said groove and of the extensions of said side walls of the groove in the second part of the needle-guide.
By this arrangement, at least but not only in the disassembled condition, the elongated hole is longitudinally completely open, whereby it may be cleaned and sterilized with the highest safety but, unlike the case of the separation plane secant to the elongated hole or cannula and parallel to the longitudinal axis thereof, a perfect mutual centering effect between the two needle-guide parts is ensured, as well as a stable hold of said proper position with reference to transverse staggering.
Obviously, alternatively to the above, instead of two extensions of the side walls of the longitudinal grooves of the second needle-guide part, the second needle-guide part may be arranged to have a single extension of one of the two side walls of the longitudinal groove, whereas the other extension may be provided on the base part, as an extension of the opposite side wall of the longitudinal groove in the base part of the needle-guide. Here, each of the two parts of the needle-guide forms two of the opposite walls of the elongated hole or cannula.
The arrangement of the extensions of the side walls of the grooves in the two parts of the needle-guide may be also alternate and complementary over the length of the two extensions in the longitudinal direction of the grooves, either on one side and along the two opposite sides.
The second part of the needle-guide may be stably and removably secured to the needle-guide base in any manner, and particularly by means of screw-threaded devices, such as fastening bolts, or the like. In a particularly advantageous embodiment, one of the parts of the needle-guide, particularly the base part, has a wall parallel to the connecting direction, i.e. perpendicular to the separation plane, which has a recess for accommodating a fastening bolt which is screwed into a threaded hole formed in the other part, in an adjacent wall, adhering against said wall of the first part of the needle-guide. Alternatively to using bolts, said second part of the needle-guide may have a threaded pin of such a length as to project beyond the wall of the first part, through the recess provided in said wall and onto which threaded pin a nut screw is tightened.
Alternatively, the two mutually adhering walls of said two parts of the needle-guide may have, the inner one, a threaded hole and the other one a through hole, a threaded bolt with a tightening head being provided to fasten said two walls together.
According to an additional characteristic, the needle-guide may have a slender or tapering head, particularly having rounded edges, especially being wedge-shaped.
As a whole, the needle-guide may have a shape tapering toward the front end, especially a wedge shape. This is particularly advantageous in combinations of the above needle-guide with endocavitary probes, such as for uterine biopsy applications or the like.
In order to limit the presence of discontinuities, which might cause damages or pain to the patient, the front head, also perforated, is arranged to be a single piece, and preferably made of one piece with the base part of the needle-guide.
In this case, the through hole in said head part is widened on at least one side or for a portion of its inner delimiting surface, the second part of the needle-guide being provided, on its end side, with a wall extension which may be axially fitted in the through hole of the front head, coinciding with said wider portion and complementary thereto so as to complete, even in the front head of the needle-guide, the delimiting wall of the elongated through hole.
Advantageously, the second part of the needle-guide has said extensions on two opposite sides and in the form of front extension wings of the two side walls of the groove provided in said second part of the needle-guide, whereas the front head of the needle-guide has complementary widened portions in the corresponding walls.
In a further improvement, the bottom wall of the groove of the second needle-guide part also has an extension wing, the front head of the needle-guide being arranged to be accordingly widened even in the area of said extension wing of the bottom side of the groove of the second needle-guide part.
The extension wings of the side and/or bottom walls of the groove in the second part of the needle-guide are thinner than the wall of the second part of the needle-guide and than the head of the needle-guide, whereby an abutment step is formed between the front end of the second part of the needle-guide and the facing rear end side of the front head.
In accordance with an additional advantageous characteristic, the front head of the needle-guide, which is integral with the base part of the needle-guide, has a through aperture which communicates with the elongated hole provided therein at at least one of the sides of said head, preferably at one of the two transverse sides, not coinciding with the extension wings of the second part of the needle-guide and particularly at the side of the base part of the needle-guide which is opposite the second part of the needle-guide and meant to adhere against or turned toward the probe, whereas in the front head, the needle is only substantially guided on three sides and through less than 360° at least in coincidence with the through aperture.
Advantageously, the front head of the needle-guide is relatively short as compared with the length of the rest of the needle-guide, in which the elongated hole or cannula have a continuous delimiting surface.
According to a further improvement, the front head of the needle-guide has a steeper tapered front end than the remaining portion of said head on the side connected to the second part of the needle-guide, whereas in said end portion and in the wall opposite the one with the aperture, the needle projection opening is provided, which takes an elongated shape, and in said end, the elongated hole delimiting walls are continuous and made of one piece, as well as directly accessible from the entry aperture.
Particularly, said front end of the front head of the needle-guide still has a needle guiding surface on the aperture side opposite to the one wherein the second part of the needle-guide fits, which surface extends from the front end of said aperture to the front apex of the front head.
As stated above, the needle-guide is designed to be mounted on an ultrasound probe, wherefore the invention also relates to a combination of a needle-guide and an ultrasound probe, wherein the base of the needle-guide is removably attachable to the probe body in a stable and predetermined position, said base having one or more shape mating extensions which adhere to a portion of the outer surface of the ultrasound probe body and/or mutual interlock engagement means, as well as clamping means.
In one embodiment, the needle-guide as described herein, having a tapered front head is designed to be connected to an endocavitary probe, which typically has a substantially cylindrical or other similar shape, also being elongated and having a rounded head, the base of the needle-guide having a surface whereby it rests on the probe case only in a few partial portions of the longitudinal extension and particularly in the end portions of the base of the needle-guide.
Further, the facing surfaces of the base of the needle-guide and of the probe case have complementary centering projections and recesses arranged over their length.
According to an improvement, the probe case may have recesses for accommodating supporting feet or extensions of the base of the needle-guide, provided at least at the ends thereof.
Particularly, the front head of the needle-guide has a front engagement extension on the side turned toward the probe case, which is designed to engage in a recess of the probe case, in such a manner that the tapered end of said front head can be connected thereto without forming outer steps or discontinuities.
In this case, since the centering pins and the means for engaging the front head of the needle-guide to the probe are effective position-holding means for the base of the needle-guide, the needle-guide is removably secured to the probe by means of a clamping collar provided at the rear end portion of the needle-guide.
An additional embodiment of the needle-guide combined with an external ultrasound probe having a bulged shape and a wider head as compared with the handgrip, has a base with two front extensions for resting on preferably symmetrically coincident front widened portions of the bulged shape, and an extension with a fastening screw which overlaps the rear side of the widened head against which the fastening screw is tightened. The fastening action so obtained is substantially concentrated in three points and is highly stable.
According to a further improvement, the needle-guide may have two, three or more elongated holes or two, three or more elongated guiding cannulae which are arranged in such a manner as to bring at least one of the needles in an ultrasound probe imaging position, whereas the other needle/s have predetermined and fixed positions relative to the former.
Hence a proper guiding action of the needle set is obtained, and the target area may be widened, for instance for a thermoablation application or for a localized injection of substances.
Advantageously, the invention proposes that this needle-guide type is also composed of two parts, a separation plane or surface being provided between the at least two parts, which is parallel to the axis of the corresponding elongated hole or cannula, and is secant or at least tangent to the corresponding hole, so that, by the separation between said at least two parts, all the elongated holes or cannulae are longitudinally open on at least one portion of a side.
Here again combinations of grooves and walls may be provided in said two parts which, by their mutual engagement, simultaneously form the complementary parts of the delimiting surfaces of the two, three or more holes in the needle-guide.
In an advantageous embodiment which includes three needle guiding elongated holes or cannulae and in which the needle-guide is divided into a base and a second part to be removably fastened to the base, the base of the needle-guide has a groove which accommodates the second part of the needle-guide, and has longitudinal side walls and a bottom wall, whereas an additional narrower groove is provided in the middle of the bottom wall and in turn has an additional groove in its bottom wall, which forms two longitudinal side walls and a longitudinal bottom wall for guiding the needle, whereas the second part of the needle-guide has, on the surface turned toward the bottom of the housing groove, a longitudinal median rib which coincides with the narrower longitudinal median groove in the base part and forms the missing needle guiding surface, completing the surfaces provided in the third groove, whereas, in the surfaces of the second part of the needle-guide, on the two sides of the longitudinal medial rib, longitudinal grooves are provided which form, with the facing surfaces of the first groove for accommodating the base part, at the two sides of the median groove, the delimiting surfaces of the two additional needle guiding elongated holes.
The advantages of the present invention are self-evident from the above description. The needle-guide device may be easily disassembled and allows to access the guiding elongated holes for a complete and safe sterilization. This allows to manufacture reusable needle-guides, from metal materials which do not involve drawbacks in various applications.
The needle-guide of the invention perfectly fits any application, as proven by the application embodiments to both endocavitary and external probes.
It shall further be noted that the individually described characteristics may be provided in any combination, even regardless of the individual specific embodiments.
The invention relates to further improvements which will form the subject of the appended claims.